Aqueous precipitation and deposition-precipitation method were used to prepare CeO2 supports and Au/CeO2 catalysts, respectively. The effect of preparation condition of support on the catalyst activity was investigate...Aqueous precipitation and deposition-precipitation method were used to prepare CeO2 supports and Au/CeO2 catalysts, respectively. The effect of preparation condition of support on the catalyst activity was investigated. The catalytic combustion of HCHO was considered as the probe reaction for comparing the catalyst activity. The BET, X-ray diffraction, X-ray photoelectron spectroscopy （XPS）, and reduction （TPR） were carried out to analyze the influence factor on the catalysts activity. The results showed that the addition of dispersant and use of microwave in the support preparation procedure could be beneficial for enhancing the interaction of supports and gold species and thus improved the catalytic activity. The total conversion temperature for HCHO was 146 ℃ over AC400. With the modification during supports preparation process, the catalytic activity increased with total conversion temperature decreasing to 98 ℃. The results of XPS indicated that Au^0 and Au^＋1 species coexisted in these catalysts and the activity of catalyst correlated with Au^＋1/Au^0 ratio. Temperature-programmed reduction results demonstrated that the reduction peak appeared between 100-170 ℃ with the inducing of gold. The dependence of activity on the reduction peak temperature implied that ionic gold was catalytic activity component for HCHO oxidation.展开更多
In the research on the gold deposits,it has been proposed that gold istransported as sulfide hydrogen complex.But from the analysis of the compositionof the fluid inclusions in gold-quartz veins,only SO<sub>4<...In the research on the gold deposits,it has been proposed that gold istransported as sulfide hydrogen complex.But from the analysis of the compositionof the fluid inclusions in gold-quartz veins,only SO<sub>4</sub><sup>2-</sup> exists and no other sulfur ionshave been found.This may be ascribed to the limitations of the composition analysismethod.By using probe mass spectrometry,gas H<sub>2</sub>S has been found in the fluid in-clusions in gold deposit。but its meaning has been neglected.In China,it is thefirst time to use probe mass spectrometry to analyse the fluid inclusions composition.展开更多
基金the National Natural Science Foundation of China (20563003)Natural Science Foundation of Inner Mongolia (200508010203)
文摘Aqueous precipitation and deposition-precipitation method were used to prepare CeO2 supports and Au/CeO2 catalysts, respectively. The effect of preparation condition of support on the catalyst activity was investigated. The catalytic combustion of HCHO was considered as the probe reaction for comparing the catalyst activity. The BET, X-ray diffraction, X-ray photoelectron spectroscopy （XPS）, and reduction （TPR） were carried out to analyze the influence factor on the catalysts activity. The results showed that the addition of dispersant and use of microwave in the support preparation procedure could be beneficial for enhancing the interaction of supports and gold species and thus improved the catalytic activity. The total conversion temperature for HCHO was 146 ℃ over AC400. With the modification during supports preparation process, the catalytic activity increased with total conversion temperature decreasing to 98 ℃. The results of XPS indicated that Au^0 and Au^＋1 species coexisted in these catalysts and the activity of catalyst correlated with Au^＋1/Au^0 ratio. Temperature-programmed reduction results demonstrated that the reduction peak appeared between 100-170 ℃ with the inducing of gold. The dependence of activity on the reduction peak temperature implied that ionic gold was catalytic activity component for HCHO oxidation.
文摘In the research on the gold deposits,it has been proposed that gold istransported as sulfide hydrogen complex.But from the analysis of the compositionof the fluid inclusions in gold-quartz veins,only SO<sub>4</sub><sup>2-</sup> exists and no other sulfur ionshave been found.This may be ascribed to the limitations of the composition analysismethod.By using probe mass spectrometry,gas H<sub>2</sub>S has been found in the fluid in-clusions in gold deposit。but its meaning has been neglected.In China,it is thefirst time to use probe mass spectrometry to analyse the fluid inclusions composition.
